Investors in embattled Herbalife raced to the exits yesterday after regulators shut down a Kentucky-based multi-level marketer it claimed is a pyramid scheme.

News of the shutdown of Fortune Hi-Tech Marketing by the Federal Trade Commission and three state regulators sparked an 8.2 percent sell-off in Herbalife shares on volume that was twice the daily average.

In court papers filed in an attempt to close the Lexington-based company, regulators claim more than 90 percent of the people who signed on with Fortune Hi-Tech Marketing lost money.

Los Angeles-based Herbalife has been under attack from hedge-fund activist Bill Ackman since Dec. 19.

Ackman claims Herbalife, a multi-level marketer of nutritional products, is a pyramid scheme.

The Ack-attack drove Herbalife’s shares down 40 percent over four days ending on Christmas Eve.

The shares had rallied since then as other hedge-fund investors have jumped in — notably Ackman’s hedge-fund rival Dan Loeb, who took an 8.2 percent stake in Herbalife.

Indeed, the once-beaten down stock had climbed above the $42.50 closing price on the day prior to Ackman’s assault. Yesterday, however, the company slid to $40.02.

Investors may have bid the shares down because Ackman’s charges are similar to those aimed at FHTM.

Ackman has made a $1 billion short bet based on his research that shows 93 percent of Herbalife distributors lose money.

Herbalife has said it cannot directly refute Ackman’s allegation.

In a statement to The Post yesterday, a company spokesman said “nearly 75 percent of [Herbalife’s] volume consists of purchases that are clearly made solely for the purposes of self-consumption or retail.”

Herbalife also noted that the company has been around for 32 years.

But the FTC’s Steven Baker told The Post that the length of time in business is no indicator of legality.